Sediment Quality Indices Research Articles

Geochemical indices for Zn, Cu, and Co in sediment cores of Coata River, Puno Region, Peru

Urban contamination resulting from the dynamics of unplanned cities has generated interest in recent decades due to increased pollutant emissions into the natural environment. The Coata River is a complex ecosystem exposed to pollution due to the high urbanization degree and consequent industrial dynamics, as well mining activities. Significant amounts of waste and pollutant substances are discharged into the river, often without any treatment, contributing to a drastic increase in the concentration of heavy metals that cause impacts and pressures on the environment. In this context, the present study contributes to the evaluation of the metal concentration (Zn, Cu, and Co) in three short sediment cores sampled at Coata River, Puno region, Peru. The acquired concentration data was compared with guideline reference values established by international sediment quality standards and used for calculations of the geochemical indices Enrichment Factor and Geoaccumulation Index. The highest concentrations were found for zinc (639 mg/kg) and copper (96 mg/kg), whilst zinc exhibited some values above the guidelines corresponding to the probable effect level (PEL, legislation of Canada) and mean range effects (ER-M, legislation of the United States). According to the sediment quality indices, the three stations range from moderately to highly contaminated with Zn, while Cu and Co show no contamination and moderate contamination, originating from both geogenic and anthropogenic sources.

Receptor model-based sources and risk assessment of metals in sediment of the coastal construction-oriented aquatic system in Bangladesh

Metal pollution in sediment from construction areas raises ecological and health concerns, yet source-based sediment pollution in Bangladesh remains understudied. Our investigation focused on fifteen locations in the Kohelia River and the coastal regions near the Matarbari projects (Matarbari Power Plant, Matarbari Deep Seaport), assessing metal concentrations' sources and impacts on ecology and human well-being. Sediment quality indices indicated high Cd and Cr contamination, with sites near Matarbari projects being the most polluted. The positive matrix factorization model identified three anthropogenic sources and mixed sources. Matarbari projects contributed significantly to As (67.9 %), Mn (50.25 %), Cd (48.35 %), and Cr (41.0 %), while ship-breaking yards contributed Fe (58.0 %), Zn (55.5 %), Pb (53.8 %), and Cu (36.1 %). Ecological indices showed different impacts on aquatic life from metal pollution, but cancer risk levels stayed below the threshold set by the US Environmental Protection Agency. These findings underscore the need for targeted measures to address metal pollution.

Comparative analysis of sediment quality indices using different reference values in an environmental protection area in Southeastern Brazil.

Contamination of aquatic ecosystems by potentially toxic elements (PTEs) is a concerning environmental issue, given their persistence, toxicity potential, and ability to accumulate in living organisms. Several studies have been conducted to assess the contamination of aquatic ecosystems by PTEs, using pollution and ecological risk indices that rely on the concentration of these elements in aquatic sediments. However, many of these studies use global reference values for calculating the indices, which can lead to misleading interpretations due to substantial variations in PTEs concentrations influenced by the geological characteristics of each region. Therefore, the use of regional reference values is more appropriate when available. This study aimed to investigate variations in the results of five indices, employing global, regional, and quality reference values, based on sediment samples collected from rivers in the Ipanema National Forest, a protected area in Brazil exposed to various anthropogenic pressures. The results revealed that elements such as Al, Fe, and Mn exceeded the limits allowed by legislation in water samples, while As and Cr surpassed the limits in sediment samples. Comparative analysis highlighted significant discrepancies in the results of the indices when global reference values were used compared to regional and quality reference values, especially for As and Ba. Thus, this study underscores the importance of establishing specific regional values for an accurate assessment of sediment quality and the risks associated with contamination by PTEs in different regions worldwide.

Sediment Quality Indices for the Assessment of Heavy Metal Risk in Nador Lagoon Sediments (Morocco) Using Multistatistical Approaches

Heavy metals in coastal ecosystems caused by the increased expansion of urbanization, industrialization, and agricultural practices have become a significant environmental risk to human well-being. This study evaluates and compares 17 sediment quality indices to examine the possible ecological and human health risks associated with heavy metal concentrations in the sediments of the Nador lagoon in Morocco. The concentration order of the HMs and sulfurs evaluated was S > Sr > Ba > V > Zr > Zn > Cr > Rb > La > Cu > Pb > Ni > Ce > Nd > Co > Sc > Nb > Ga > Th > Y > Hf. Sulfurs, Pb, Sr, and Nd exhibited concentrations that exceeded geochemical background values. The analysis of the sediment quality indices allowed us to understand that the Nador lagoon was moderately to strongly polluted by heavy metals originating from various anthropogenic activities. Results from the Sediment Quality Guidelines indicated a toxic response in the benthic organisms within the lagoon, while the ecological hazard analysis revealed a very high risk of heavy metal contamination in the ecosystem. The Hazard Index for non-carcinogenic values was below the limit, suggesting a lack of non-cancerous effects. However, Cu and Pb concentrations surpassed the Lifetime Cancer Risk range, indicating a potential cancer risk with prolonged exposure. Integrating our research into coastal management frameworks can contribute to the preservation and enhancement of these coastal ecosystems for future generations.

Growth Performance and Environmental Quality Indices and Biomarkers in a Co-Culture of the European Sea Bass with Filter and Deposit Feeders: A Case Study of an IMTA System

This study aimed to evaluate the efficiency of an integrated multi-trophic aquaculture (IMTA) system comprising co-cultured fed fish and organic extractive species representing three distinct trophic levels as well as the impact and potential utilization of two commercially available fish feeds made up of 35% fish meal (FM) and 20% fish meal (LFM) ingredients, using a multi-indicator assessment approach. Significant alterations were observed in growth performance indicators (GPIs), water and sediment quality indices, toxicity tests and biomarkers within the IMTA system. The fish survival, weight gain (WG), and specific growth rate (SGR) were higher in the IMTA system with significantly lower feed conversion ratios (FCRs) and higher feed efficiency (FE) in comparison to the fed fish monoculture system. Yet, organic filter feeders displayed 100% survival, and increased shell growth, while deposit feeders exhibited successful survival and significant weight gain. In the comparison between FM-IMTA and LFM-IMTA, fed fish in FM-IMTA showed higher WG, SGR, and FE with lower FCR. Environmental parameters like temperature, oxygen, and nutrient concentrations fluctuated but generally improved in the IMTA system, indicating lower mesotrophic conditions. Sediment fatty acid profiles differed between systems and toxicity assessments, which suggested a lower impact in IMTA and FM-IMTA systems. The sediment microbial community displayed high similarity within IMTA systems and between FM-IMTA and LFM-IMTA. These findings underscore the potential of IMTA systems for sustainable aquaculture, emphasizing improved growth performance and reduced environmental impact, particularly when using fish meal feeds.

Legacy contaminant trends in the Great Lakes uncovered by the wildlife environmental quality index

Since the 1970s, wildlife managers have prioritized the recovery of Great Lakes ecosystems from contamination by Persistent Organic Pollutants (POPs). Monitoring and quantifying the region's recovery is challenged by the diversity of legacy contaminants in the environment and the lack of benchmarks for their potential biological effects. We address this gap by introducing the Wildlife Environmental Quality Index (WEQI) based on prior water and sediment quality indices. The tool summarizes, in a single score, the exposure of wildlife to harmful levels of multiple contaminants – with harmful levels set by published guidelines for protecting piscivorous wildlife from biological impacts. We applied the new index to a combined Canadian and American dataset of Herring Gull (Larus argentatus) egg data to elucidate trends in wildlife for eight legacy industrial pollutants and insecticides in the Great Lakes. Environmental quality of the Great Lakes region (as indexed by WEQI) improved by 18% between 2002 and 2017. Improvement came from reductions in both the scope of contamination (the number of guideline-exceeding contaminants) and its amplitude (the average size of guideline exceedances) at bird colonies. But recovery was unequal among lakes, with Lake Erie showing no improvement at one extreme. Weakly- or non-recovering lakes (Erie, Ontario, Huron) were marked by inconsistent improvement in scope and amplitude, likely due to ongoing loading, sediment resuspension and other stressors reported elsewhere. Fast-recovering lakes (Superior and Michigan), meanwhile, improved in both scope and amplitude. Contrasting trends and contaminant profiles (e.g., exceedances of PCBs versus DDTs) highlight the importance of lake-specific management for equalizing recoveries. Lower environmental quality at American than Canadian colonies, particularly in Lake Huron, further suggest uneven success in – and opportunities for – the binational management of wildlife exposure to legacy contaminants.

Spatiotemporal variability of heavy metals concentration in an industrialized estuarine-bay ecosystem in Northern Persian Gulf

<p>This study aimed to evaluate the pollution level of Ni, Pb, Cd, V, and Hg in the sediments of Musa Estuary and its four main tributaries namely Majidieh, Zangi, Semaili, and Merimos (collectively known as Mahshahr estuaries) in summer and winter 2019 using sediment quality indices. In each tributary, 4 stations were chosen to represent the estuary condition. One control point was also considered at the mouth of the estuary (17 stations in total). 51 sediment samples were collected using the Van Wien Hydrobius grab sampler and measurements were performed utilizing the ICP-MASS device. The heavy metals concentration was ordered as Ni> Pb> Cd> V> Hg and tributaries followed the order of Majidiyeh> Samaili> Zangi> Merimos> Musa's mouth (control point) in terms of heavy metal concentration in both seasons. Heavy metal concentrations were positively and significantly correlated with electrical conductivity and pH (P <0.05). The potential ecological risk (Er) was low for Ni, Pb, and V, moderate for Cd (except for Musa's mouth in summer (27.33)). Hg had low risk in Zangi Tributary and Musa's mouth in summer and medium risk in other tributaries in winter. The ecological risk index (RI) showed considerable risk in Zangi Tributary and Musa's mouth in both seasons and high risk in Merimos, Majidieh, and Samaili tributaries. According to the pollution load index (PLI), the sediments of Mahshahr estuaries showed no pollution in summer and moderate pollution in Majidiyeh and Smaili tributaries in winter. The Nemro Integrated Pollution Index ranged from 8.62 to 20.04 in summer and 9.15 to 21.53 in winter Mahshahr estuaries which indicate its high pollution potential. The findings of this research and those of previous studies alarm increasing levels of heavy metals’ content in the sediments of Mahshahr estuaries over the past years.</p>

Assessment of Heavy Metal Contamination in Beach Sediments of Eastern St. Martin’s Island, Bangladesh: Implications for Environmental and Human Health Risks

Heavy metal pollution in marine ecosystems is an escalating environmental concern, largely driven by anthropogenic activities, and poses potential threats to ecological health and human well-being. This study embarked on a comprehensive investigation into the concentrations of heavy metals in sediment samples and evaluated their potential ecological and health risks with a focus on Eastern St. Martin’s Island (SMI), Bangladesh. Sediment samples were meticulously collected from 12 distinct sites around the island, and the concentrations of heavy metals, including Mn, Fe, Ni, Zn, Cr, Pb, and Cu, were quantified utilizing atomic absorption spectrometry (AAS). The results revealed that the average concentrations of the metals, in descending order, were Mn (269.5 ± 33.0 mg/kg), Fe (143.8 ± 21.7 mg/kg), Ni (29.6 ± 44.0 mg/kg), Zn (27.2 ± 4.34 mg/kg), Cr (8.09 ± 1.67 mg/kg), Pb (5.88 ± 0.45 mg/kg), and Cu (3.76 ± 0.60 mg/kg). Intriguingly, the concentrations of all the measured metals were found to be within permissible limits and comparatively lower than those documented in various national and international contexts. The ecological risk assessment, based on multiple sediment quality indices such as the geoaccumulation index, contamination factor, and pollution load index, indicated a moderate risk to the aquatic ecosystem but no significant adverse impact on sediment quality. Additionally, the human health risk assessment, encompassing non-carcinogenic hazard indices for different age groups, was considerably below the threshold, signifying no immediate health risk. The total carcinogenic risk was also found to be below acceptable levels. These findings underscore the current state of heavy metal pollution in Eastern St. Martin’s Island, providing valuable insights for environmental monitoring and management. While the immediate risks were not alarming, the study highlights the imperative need for sustained monitoring and the implementation of rigorous regulations to curb heavy metal pollution in order to safeguard both ecological and human health. This warrants the development of policies that are both adaptive and preemptive to ensure the sustainable utilization and conservation of marine resources.

Sedimentary PAH and oxidative stress biomarkers responses on Namalycastis abiuma (Polychaeta: Nereididae) from an urbanized Amazon estuary

Contamination by polycyclic aromatic hydrocarbons (PAH) in sediments and oxidative stress biomarkers responses (glutathione-S-transferase activity—GST and lipoperoxidation—LPO) on the polychaetes Namalycastis abiuma were screened along the urbanized margin of the Guajará Estuary, Brazilian Amazon coast, during dry and rainy seasons. Total 16 priority PAH concentrations ranged from 17 to 386 ng g−1 dry sediment, with higher values during the dry season. High molecular weight PAHs predominated during dry season and were probably originated from fossil fuel burning. Increased naphthalene and anthracene concentrations were noted when the maximum river flow was recorded and suggest diffuse sources from drainage of contaminated surfaces. Ecotoxicological PAH risks were low according to international sediment quality indices. Nevertheless, PAH toxicity equivalency was around 10-fold higher nearer the oil terminal than alongside the estuary. Highest GST activities at the oil terminal and industrial sites coincided with the rainy season, and combined with hydrochemical and sedimentary conditions thought to promote PAH bioavailability and a prolonged toxicant exposure. LPO approached similar levels in both seasons, suggesting that enzymatic activities were sufficient to uphold the prooxidants exposure. This result indicates that the overall estuarine condition exerts subtle oxidative stress on a keystone species and matches the low PAH ecotoxicological risks. Depositional margins within the mangrove areas and port operation are susceptible to an enhanced PAH accumulation and need special surveillance.

Comparing the applicability of ecological risk indices of metals based on PCA-APCS-MLR receptor models for ports surface sediments

This study collected surface sediments from seven ports in Taiwan and analyzed their characteristics along with 10 metals. Enrichment factor (EF), relative EF (REF), potential ecological risk index (PERI), and mean effect range median quotient (m-ERM-q) were used to evaluate the levels of metal contamination and ecological risks in sediments. Principal component analysis (PCA) and the absolute principal component score-multiple linear regression (APCS-MLR) model were applied to quantify the main factors affecting the variations in sediment metals. The different normalization techniques that vary between indexes significantly affect the estimates of risk levels for sediment metals. APCS-MLR model confirmed the significant difference among the sediment quality indices in the degree of anthropogenic pollution, ranging in the order of REF (normalized with reference site and Fe, 97.0 %), PERI (normalized with reference site, 85.5 %), EF (normalized with crust and Fe, 79.4 %), and m-ERM-q (not normalized, 56.6 %).

An assessment of water and sediment quality of aquatic ecosystems within South Africa’s largest floodplain

Ndumo Game Reserve (NGR), a Ramsar site, situated in South Africa’s largest floodplain (Phongolo River floodplain) in northern KwaZulu-Natal, with important aquatic ecosystems: the Usuthu and Phongolo rivers and their associated floodplain lakes. While the Phongolo River is regulated, the Usuthu River is unregulated and subjected to fewer anthropogenic activities that influence the downstream environmental quality of this Ramsar system. The present study evaluates the environmental quality of floodplain systems in the NGR. Water and sediment were sampled and analysed from both rivers and associated floodplain lakes during different hydrological periods (flow). Using multivariate statistical techniques, ionic compositions, as well as water and sediment quality indices of the ecosystems were evaluated. Key findings suggest spatial and flow-related differences, which highlight the human-driven impacts from the upper catchments and the rivers influence on their respective floodplain lakes. The environmental quality (water and sediments) could be classified as ‘good’ and predominantly unimpacted. Notably, ionic composition of river water showed the importance of the unregulated Usuthu River and its contribution to aquatic ecosystems within the NGR and their continued functioning. The quality indices further indicated that metals do not currently pose any ecological risks to these systems.

Evidence that offshore wind farms might affect marine sediment quality and microbial communities

Offshore wind power is a typical example of clean energy production and plays a critical role in achieving carbon neutrality. Offshore wind farms can have an impact on the marine environment, especially sedimentary environments, but their influence on sediments remain largely unknown. This study, which uses the control-impact principle to define different areas, investigated the characteristics of marine sediments under the Putidao offshore wind farm in Bohai Bay, China. We used chemical and microbiological observations to evaluate sediment quality and microbial community structure. According to both the geo-accumulation index (Igeo) and contamination factor (CF) indexes, copper, chromium and zinc were the major contaminants in the offshore wind farm sediments. The pollution load index (PLI) index showed that the various sites on the wind farm were only lightly polluted compared with baseline values. Closer to the wind farm's center, the metal concentrations started to rise. The physicochemical features of the sediments could better explain changes in the microorganisms present, and screening the microbiomes showed a correlation with heavy metal levels, linking the relative abundance of microorganisms to the sediment quality index. This comprehensive study fills a knowledge gap in China and adds to our understanding of how to assess the sedimentary environments of offshore wind farms.

Characterization and Risk Assessment of Heavy Metals in Surface Sediments From Jian and Moyang Rivers in Western Guangdong

The river environment is complex and receives a variety of contaminants from numerous sources that are persistent, bioaccumulative, and toxic. The distribution, source, contamination, and ecological risk status of Zn, Pb, Cu, Ni, Cr, and Cd were evaluated in the surface sediments at 45 sites on the Moyang and Jian rivers in Western Guangdong, China. Single pollution indices, including contamination factor (CF) and enrichment factor (EF), revealed that Zn, Pb, Ni, Cu, and Cd showed moderate to significant enrichment. To overcome the limitation of the single element indices, a range of sediment quality indices, including modified contamination index (mCd), pollution index (PI), and modified pollution index (MPI), were utilized to ascertain the sediment quality. The sediment in the study area is deemed to be slightly to extremely polluted. The sediment quality guidelines (SQGs), potential ecological risk index (RI), and modified ecological risk index (MRI) were used to assess possible ecological risks. According to the SQGs, Pb, Ni, and Cu have the potential to induce biological effects. The RI indicated that the sediment poses a low ecological risk. However, the MRI indicated that the ecological risk of the sediment was moderate to very high. The accuracy of the single and multi-element indices and ecological risk assessment were evaluated in the river using the principal component analysis (PCA) and cluster analysis (CA), showing an anthropogenic impact. Results demonstrate the need to pay attention to the ecological environment of small rivers, which are sensitive to their surroundings.

Pollution level of trace metals (As, Pb, Cr and Cd) in the sediment of Rupsha River, Bangladesh: Assessment of ecological and human health risks

The study area was selected in the Rupsha river basin and the sediment samples were collected to determine trace metal concentrations of As, Pb, Cd, and Cr along with biological effects, and potential ecological and human health hazards for adults and children. The concentrations of trace metals were detected from sixty composite sediment samples using an Atomic Absorption Spectrophotometer (AAS) following some sequential analytical procedures. The mean concentrations of trace metals were organized in the descending order of chromium (Cr) (43.2 mg/kg) > lead (Pb) (29.21 mg/kg) > arsenic (As) (5.18 mg/kg) > cadmium (Cd) (1.8 mg/kg). The current study highlighted that metals were attributed to the riverine sediments from natural sources and other anthropogenic sources, particularly from various industries. Based on the effect-range classifications of threshold effect concentration (TEC) and probable effect concentration (PEC), the trace metal concentrations can impact on the sediment-dwelling organisms occasionally especially for Cr, Cd, and Pb. That is, the concentrations had negative biological consequences on aquatic creatures. The assessed potential ecological risk of Cd offers a significant risk to the aquatic ecosystem, whereas As, Cr, and Cd were in low-risk. Most of the sites of the study area were within the range of moderate risk, indicated by the risk index (RI) values. Furthermore, the applied sediment quality indices, geo-accumulation index (Igeo) indicated that sediment was contaminated by Cd whereas contamination factor (CF) denoted that the sediment of the study area was moderately polluted by Pb. However, pollution load index (PLI) revealed that the study area was polluted for cumulative sence especially in winter season. The age-group risk index (HI) was much lower than the threshold limit of 1, showing that the pollution had no non-carcinogenic risk effect. Total carcinogenic risk (TCR) was less than one-tenth of a percentile. For the sake of human and environmental health, proper monitoring of metal element attribution and strict regulation are required to lessen trace metal pollution.

Water and sediment geochemistry of an urban lake: Implications to weathering and anthropogenic activity

Lakes are sensitive ecosystems and respond quickly to any natural or anthropogenic contamination, particularly in urban areas due to poor planning and mismanagement in urban settlement, encroachment, and anthropogenic pollution. In the current study, water and sediment geochemistry are used along with available time series of geospatial data sets to assess: a) provenance and sources of pollution in the lake sediment and water, b) health risk using various sediment and water quality indices, and c) the key drivers of lake shrinkage. Chemical index of alteration (CIA) of lake sediment is higher (>85) with an atypical cluster of samples (CIA = 50–75) towards the south and west of the lake. Further, samples in this cluster show granodioritic provenance which is contrary to the overall mafic provenance of lake sediment. The unusual decrease in CIA in the southern and western side of the lake is attributed to anthropogenically induced fresh sediment in the lake. The results indicate that the sediment is highly polluted by cadmium (Cd) and moderately polluted by copper (Cu), molybdenum (Mo), lead (Pb), and boron (B). Higher Metal Index (MI) values for most of the water samples (>70%) and Hazard Index (HI) for chromium (Cr), nickel (Ni), and cadmium (Cd) towards west and south of the lake reflect the deterioration of water quality in the lake. Moreover, land use change detection attained from available time series of geospatial data sets indicate a drastic transformation of the open water area into other land use classes particularly human settlement, shrinking the lake open water area by 13 km2 since 1859. The current study will help policy makers and managers to restore and conserve the lake.

Ecological risk assessment of the riverine and deltaic environments (Rozechai River, Urmia Lake, Iran), using sediment quality indices.

Rozechai River is one of the tributaries of Urmia Lake (the nrthwest of Iran), which has experienced severe pollution and water level fluctuations in the coastal zone over the past four decades. The present study aimed to assess the ecological risk for aquatic life and human health. Research methods were designed for applying the sediment quality guidelines (LEL, PEL, SEL), sediment quality indices (Cf, Cd, Er, RI), and enrichment factor (EF) based on the concentration of toxic metals in sediments. Event-based geochronology of the sediment column showed that the high stands in the water level of the Urmia Lake (> 1274m) occurred in 1983, 1989, and 1995. Thus, As, Pb, Zn, Cd, Cr, and Ni reached a moderate to considerable enrichment under the oxidation and alkaline condition. Consequently, a moderated level of ecological risk index (RI) was predominant between 1983 and 1999. The uppermost 35cm of the sediment column was deposited during a severe drought period to which H2S bearing water and reducing status contributed. In such conditions, the low ecological risk was resulted in the basin due to the lower rate of the toxic metal influx. The industrial, urban, and agricultural wastewaters contributed to the release of toxic metals and the dominance of moderate to considerable enrichment, which led to a moderate ecological risk at the coastal zone of the Rozechai River. The sediment column of the deltaic area has experienced a mean sedimentation rate of 1.66cmyear-1 since 1982.

Potentially Toxic Elements (PTEs) contamination and ecological risk of sediment in the upper course of the Ankobra River, Ghana

Metals, when introduced into a high pH aquatic environment, generally sink into bottom sediments and can pose a direct and indirect threat to aquatic organisms as well as humans. The concentrations of ten heavy metals (Mn, Fe, Cd, Cu, Cr, Pb, Hg, As, Zn, and Al) in the surface sediment samples from the upper part of the Ankobra, which is an illegal mining (Galamsey) prone area, were assessed in both the dry and wet seasons. To ascertain the quality of sediments, sediment quality indices, including enrichment factor (EF), index of geo-accumulation (I-geo), and modified pollution index (MPI), were employed. A comprehensive potential ecological risk assessment was also carried out using the consensus-based sediment quality guideline (CBSQG) as well as the modified potential ecological risk index (MPERI). In general, the sediment is considered to be "slightly" to "moderately" polluted in the dry season as well as "moderately" to "heavily'' polluted in the wet season. The potential ecological risk of the metals in the sediments was within the considerable to high-risk grade for Hg, moderate to considerable risk for Cd, low to moderate risk for As, and low risk for Cu, Cr, Pb, and Zn. The order of decreasing potential ecological risk for the metals is Hg > Cd > As > Cu > Pb > Cr > Zn and the risk in the wet season was higher than that in the dry season.

Assessment of Mangrove Sediment Quality Parameters from Different Seasons, Zones and Sediment Depths

Heavy metal concentrations have risen throughout Malaysia's coastline because of industrial wastewater discharge, affecting mangrove ecology significantly. Lead (Pb), Zinc (Zn), Chromium (Cr), and Nickel (Ni) were used to establish the Mangrove Sediment Quality Index (MSQi), which assesses and monitors the quality of mangrove sediment. This study was conducted at Matang Mangrove Forest Reserve (MFFR) in Perak, Malaysia to examine changes in MSQi features across seasons, mangrove zones, and sediment depths at three separate MMFR locations. Sediment samples were taken using auger in two different seasons (dry and wet seasons). After the silt was removed using aqua regia techniques, heavy metals were examined using an Atomic Absorption Spectrophotometer. According to MSQi criteria in various seasons at three different locations, the highest concentration of heavy metals (HMs) was detected in the dry season in the least disturbed region at three different locations. During dry seasons, only Cr and Ni levels are higher in moderately and highly disturbed areas. Pb and Zn levels in moderately and highly disturbed areas are higher than in least disturbed areas during the rainy season. MSQi parameters in different mangrove zones at three locations showed that most HMs content is highest in the landward zone and it can be concluded that HMs sources are anthropogenic. Furthermore, MSQi measurements at three locations revealed that heavy metals content is highest at 015 cm and lowest at other depths.

Marine shrimps as biomonitors of the Fundão (Brazil) mine dam disaster: A multi-biomarker approach

The disruption of the Fundão dam released 43 million m3 of mine tailings into the Doce River until it flowed into the ocean through the estuary. The mine tailing changed the composition of metals in water and sediment, creating a challenging scenario for the local biota. We used multivariate analyzes and the integrated biomarker response index (IBR) to assess the impact of mine tailings on the bioaccumulation profile (As, Cd, Cr, Cu, Fe, Mn, Pb and Zn) as well as the biomarkers response in gills, hepatopancreas and muscle of shrimps sampled from different sectors during two dry seasons (dry1 and dry2) (Sep/Oct 2018; 2019) and two wet seasons (wet1 and wet2) (Jan/feb 2019; 2020). There was seasonal and local effect under bioaccumulation and biomarker response revealing that the pattern responses seen in each sector sampled changed according to the season. The greater IBR added to the strong association among the most metals tissue content (Cd, Cr, Cu and Mn) and sectors sampled during dry 1 suggests greater bioavailability of these metals to the environment in this period. Estuarine sectors stand out for high Fe bioavailability, especially during wet1, which seems to be associated with greater metallothionein content in hepatopancreas of shrimps. Native species of marine shrimps proved to be successful indicators of sediment quality besides being sensitive to water contamination by metals. The multi-biomarkers approach added to multivariate analysis supports the temporal and seasonal effects, signalizing the importance of continuous monitoring of the estuarine region to better know about the bioavailability of these metals, mainly Fe, and their long-term effects on the local biota.

Accumulation potential of heavy metals at different growth stages of Pacific white leg shrimp, Penaeus vannamei farmed along the Southeast coast of Peninsular India: A report on ecotoxicology and human health risk assessment

This study compared the heavy metal concentration in water, sediment, and shrimp at different growth stages of culture and subsequently evaluated the ecotoxicological and human health risk status. Total trace element concentration in the water, sediment and shrimp ranged from not detected (ND) (Hg) to 91.05 (Fe) μg/L, 0.01 (Hg) to 19, 246.33 (Fe) mg/kg, and ND (Hg) to 13.98 (Fe) mg/kg, respectively. Toxic metals such as, Cd, Hg, and Pb in shrimps ranged from ND to 2.11 mg/kg, ND to 0.158 mg/kg, ND to 0.088 mg/kg, and ND to 0.469 mg/kg, respectively. Toxic heavy metals at all the growth stages of shrimps (days of culture (DOC)-01 to DOC-90) were found below the maximum residual limit (MRL) of 0.5 mg/kg set by the European Commission (EC). Similarly, Cu, Zn, and As concentrations in shrimp were also far below the MRLs of 30 mg/kg, 100 mg/kg, and 76 mg/kg set by the World Health Organization and Food Safety and Standard Authority of India, respectively. The concentration of heavy metals increased from DOC-01 to DOC-90 and was positively correlated with the length and weight of the shrimps (p < 0.05). The risk assessment was estimated for both Indians and Americans and found no carcinogenic (lifetime cancer risk (LCR) < 10−4) and non-carcinogenic (THQ and TTHQ<1) health risks through consumption of shrimp cultured in this region. The hazard quotient (HQdermal < 1), hazard index (HI < 1), and LCR (<10−4) values of the heavy metals indicated that the dermal absorption might not be a concern for the local fishermen and marine fish/shrimp farmworkers. Water and sediment quality indices were applied to assess the surface water and sediment quality, and their results were found nil to low levels of heavy metal contamination at all the sampling sites. All heavy metals studied in sediments were < effect range low (ERL) and < threshold effect level (TEL), indicating no adverse biological effects on aquatic organisms. Therefore, regular monitoring of the shrimp aquaculture system throughout the crop will provide evidence of heavy metals bioaccumulation in shrimps. This research will provide baseline data to help farmers establish the optimal aquaculture practices and regulatory authorities to formulate legislation and strategies to reduce heavy metal biomagnification in shrimps from farm to fork.